Buzz Johnson, who has died aged 62 from an arterial haemorrhage, was the founder of Karia Press, one of the small but dedicated band of African-Caribbean publishing initiatives in the UK that have had an impact remarkably disproportionate to their modest size and limited resources. With little more than his own energies and innate political instincts, Johnson ran his company almost single-handedly; yet since its beginnings in London in the early 1980s, Karia consistently punched above its weight, producing more than 50 titles relevant to the struggles of peoples of the Caribbean, Africa, the African diaspora and developing nations in general, often by new writers who went on to greater success.

The educationist Chris Searle, a Karia author and friend, marvelled at Johnson's ability to publish so many important books "under his own steam with no money" and noted that he helped to support some important careers by backing work "that other publishers would not touch".

Although not a man to covet the limelight, Johnson also made an invaluable contribution as an author himself, when in 1984 he produced the landmark publication I Think of My Mother: Notes on the Life and Times of Claudia Jones, which focused attention on Jones, a feminist black nationalist and "mother" of the Notting Hill carnival whose significance, 20 years after her death, had not been fully acknowledged.

Born in Buccoo, a village in Tobago, Buzz moved at a young age, along with his sisters, Vero and Cynthia, and their parents, Arthur and Adwina, to Fyzabad in the south-west of Tobago's sister island, Trinidad. There his father worked in the oilfields and, having been politicised by the trade unionist legacy of powerful local labour leaders such as Tubal Uriah "Buzz" Butler, bestowed on his son the name by which everyone came to know him.

Johnson attended school and technical college in Trinidad, then won a scholarship to continue studies as a mechanical engineer in Britain, relocating in the 1970s. Before long he transferred his attention to learning publishing and printing, setting up his small press as a response to the dearth of outlets for black and progressive writers.

Almost obsessively driven and resourceful, Johnson was involved with setting up several community ventures, among them the Claudia Jones Organisation, founded in 1982 to provide support for women and families of African-Caribbean heritage, Hackney Black People's Association, supplementary schools and community advice centres. He was also an original member of the award-winning Ebony Steel Band in London.

He maintained proud links with Tobago and had just returned from visiting his mother there when he died.

Although an abundance of ideas often outstripped his capabilities and financial means, Buzz never gave up. His reticent smile masked an indomitable spirit, admirably stubborn aspirations and a commitment to educate the next generation, represented in his own talented children, Amandla, Themba and Jamila, who survive him, as does Adwina.

• Buzz (Norris Chrisleventon) Johnson, publisher and community activist, born 2 November 1951; died 11 February 2014